operating system (Or "drop-down list") A graphical userinterface component that allows the user to choose one (or

sometimes more than one) item from a list. The current choice

is visible in a small rectangle and when the user clicks on

it, a list of items is revealed below it. The user can then

click on one of these to make it the current choice and the

list disappears. In some cases, by holding down a modifier

key such as Ctrl when clicking, the selection is added to (or

removed from) the set of current choices rather than replacing

it.